Fired heater



Aug. 9, 1966 A. LEE ETAL 3,255,043

FIRED HEATER Filed June 29, 1965 3 Sheets-Sheet l Z/ vvs- 175515 F. q. LEE G. H S/UB Aug. 9, 1966 F. A. LEE ETAL 3,265,043

FIRED HEATER Filed June 29, 1965 3 Sheets-Sheet 2 United States Patent 3,265,043 FIRED HEATER Frank A. Lee, Westwood, and George Kratsios, Verona,

N.J., assignors to Foster Wheeler Corporation, Livingston, N..l., a corporation of New York Filed June 29, 1965, Ser. No. 467,922 1 Claim. (Cl. 122-360) This invention relates to fired heaters, and more particularly, to an improved construction of a header arrangement for use in fired heaters.

In fired heaters, particularly those in which tubes are placed in a row along a vertical plane, it has been recognized that expansion of the outlet header results in severe thermal stresses in the connecting leads between the header and the fired heater tubes. In the past, to compenate for the horizontal expansion of the header and still connect the vertical tubes to the header, large loops or pigtails were used. These groups had suflicient length so that they were adequately flexible to permit the horizontal headers to expand while the vertical tubes within the fired heater remained fixed at least in the direction of expansion of the horizontal header.

Therefore, it is an object of this invention to provide a fired heater of an improved and more economical construction.

Another object is to provide a fired heater having an improved header arrangement.

In accordance with this invention, an enclosure provide a chamber into which hot gases and flame are injected by burners projecting into the chamber through the enclosure. Vertical tubes are suspended within the chamber and extend slightly beneath the bottom of the chamber. At the lower ends of the tubes, the tubes are reduced to a substantially smaller diameter than the main body of the tubes. A header runs horizontally along the lower end of the tubes, the longitudinal axis of the header and the longitudinal axis of the tubes being at approximately right angles with one another while also being in a common plane. The reduced portion of the tubes penetrates into the header which has a diameter larger than the tubes thus making possible insertion of the reduced portion through an opening in the header. An extension in the form of a continuation of the reduced portion also penetrates through the header and has a cap on its lower end for the removal of catalyst located within the vertical tubes. The extension and reduced portion have a common longitudinal axis and extend very close to one another, the opening between them providing for expansion.

This invention may be better understood from the following detailed description considered in conjunction with the accompanying drawings in which:

FIGURE 1 is a front elevation of a fired heater utilizing the invention;

FIGURE 2. is a cross-sectional view along line 22 of FIGURE 3;

FIGURE 3 is an enlarged view of a portion of FIG- URE 1.

Referring now to the drawings and more particularly to FIGURES l and 3, an enclosure 21 forms a chamber 23. The enclosure 21 is formed of multilayers of insulating and structural material. Extending upward from the chamber 23 is a convection compartment 25 in which convection tube 27 are located. Through the enclosure 21 are ports 29 through which burners 31 are inserted to provide flame and hot gases within the chamber 23 which pass upward through the convection compartment 25 and out to the atmosphere. Located along a vertical centerline of the chamber 23 is an arch opening 33. Directly beneath the arch opening 33 is a bottom opening 35. Extending downward from the bottom opening 35 is a lower extension 37. Extending from slightly above the arch opening 33 to slightly below the lower end of the lower extension 37 is a row of tubes 41 which are vertically oriented in a common plane.

Located at the lower end of the row of tubes 41 within the lower extension 35 is a lower header 44. The upper ends of the row of tubes 41 are secured to a winch system or weight and pulley arrangement 49. The winch system 49 is secured to a structural frame 61 which also supports the entire unit including the enclosure 21 and the convection compartment 25.

Fluid is supplied to the tubes 41 from an upper header 45 through connectors 46. The connectors 46 enter the tubes 41 at a point toward their upper ends. Since the connectors 46 are sufliciently flexible to accommodate the thermal expansion of the upper header 45, growth of the tubes 41 along their longitudinal axis is compensated for by the upward movement permitted by the weight and pulley arrangement 49 and the flexible assembly which supports the upper header 45.

Each of the tubes 41 is connected to the header 44 in the same manner. As shown in FIGURE 3, the tubes 41 each have a reduced end portion 63 which is of substantially smaller diameter than the tubes 41. The reduced end portion 63 which is inserted into the header 44 through an opening 64 has perforations 65 in it to permit the fluid within the vertical tube to flow outward into the header while still retaining catalyst (not shown) within the tube 41. An extension piece 67 of approximately the same diameter as the reduced end portion 63 extends along the same longitudinal axis from a separation 68 of approximately /16 inch away from the end of the reduced end portion down through an opening 69 in the header to provide for expansion. The lower end-s of the extension pieces 67 is closed with removable caps 71. The caps 71 are required to remove catalyst and to retain the catalyst within the tubes 41 during operation. Similarly, upper caps 72 are provided at the upper ends of the tubes 41 to insert catalyst into the tubes 41. A separation 68 between the reduced portion 63 and the extension piece 67 is to permit expansion of these members within the lower header 44 without distorting the shape of the lower header 44. As seen in FIGURE 3, an outlet tube 70 connects with the lower header 44 approximately at the center of the lower header 44.

Previously, with a lower header 44 separately connected to the tubes, large loops are required to prevent the connectors from breaking under the stress created by the thermal expansion of the header. A can be readily seen, expansion of the lower header causes the tubes to bow. Since the vertical tubes 41 have a sufficient length to permit them to bend or bow with the thermal expansion of the lower header 44, the cost of installing large loops is eliminated.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and numerous changes in the details of construction, and the combination and the arrangements of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

A fired heater comprising:

an enclosure forming a chamber;

means for supplying hot gases to said chamber;

a row of vertical tubes adapted to contain a catalyst and located in a common plane within said chamber, each tube having a lower end portion with a substantially reduced diameter, said lower end portion having perforations therein, said perforations stantially directly opposite the upper series into being adapted to retain the catalyst within the which the lower extensions are located, the lower illbes; end portions and lower extensions extending very means 50? pp y fluid into Said tube at a Point close to one another within said header so as to toward thfi pp end of said tubs; 5 retain the catalyst within the vertical tubes; and a row of lower extensions in the form of short tubes means for removing fluid from the header.

having approximately the same cross-sectional dimensions as said lower end portions; References Cited by the Examiner a header located in the same plane as said row of tubes and having its longitudinal axis at approxi- 10 UNITED STATES PATENTS mately right angles to the longitudinal axis of said tubes, said header having an upper series of spaced 3127248 3/19 Komeiwlez et 23*288 openings therein into which the entire perforated 3,215,502 11/19 Korwm 122-356 X portion of the lower end portions of said tubes are located and a lower series of spaced openings sub- KENNETH SPRAGUE Pr'mary Exammer' 

